Description: The most important Byzantine architecture found in Istanbul consists of churches. The most magnificent of all of the Byzantine churches is the Hagia Sophia. This church was designed by the architects Anthemios of Tralles and Izidorus of Miletus. This construction of the second Hagia Sophia was started in 532 by the order of the Emperor Justinian and was built over the ruins of an earlier structure. Materials were brought from Ephesus, Athens, Rome, and Delphi and were used in the construction of this magnificent building. The church was opened for worship five years later, in 537. The Hagia Sophia has a diameter of 31-33 meters and a height of 54 meters and is covered with a large dome. The church was considerably damaged by the earthquake of 557 and the nephew of the Architect Izidorus supervised the repair of the structure.